1. Technical Field
The present invention relates to class discovery, and more particularly, to a system and method for mild cognitive impairment class discovery using gene expression data.
2. Discussion of the Related Art
Alzheimer's disease (AD) is a progressive neurodegenerative disorder and is one of the most common causes of dementia in the elderly and is one of the leading causes of death in developed countries. AD is clinically characterized by progressive intellectual deterioration together with declining activities of daily living and neuropsychiatric symptoms or behavioral changes.
An early symptom of AD is memory loss, which usually manifests itself as minor forgetfulness that increases with the progression of the disorder. As the disorder progresses, cognitive impairment extends to the domains of language (e.g., aphasia), coordinated movement (e.g., apraxia) and recognition (e.g, agnosia) and to functions such as decision-making and planning that are closely related to the frontal lobe of the brain.
If an effort to find a cure for AD, the molecular mechanism of AD has drawn much attention, but its pathogenesis is still largely undetermined. For example, it is still uncertain as to whether the central mechanism of AD neuro-degeneration is β-amyloid or neurofibrillary tangles (NFT) of tau protein. Recently, mild cognitive impairment (MCI), which is a syndrome of memory impairment that does not significantly affect daily activities and is not accompanied by declines in overall cognitive function, has been identified as a potential transitional stage between normal aging and dementia.
For example, research has found that between 6 to 25 percent of people with MCI progress to AD. Further, many experts have posited that MCI as well as typical age-related memory loss is an early form of AD and thus progression to symptomatic AD would eventually occur. Thus, MCI is becoming increasingly recognized as a risk factor for AD.
Global genomic mapping of the brain and medical imaging of the brain have been used to understand the structure and function of a variety of diseases. This analysis has also been used on AD patients to gain further insight into gene expression in healthy and diseased brains.
Although gene expression analysis has shown promise in identifying an d aiding in the treatment of AD, it has not been used to definitively identify what causes the onset of AD. Accordingly, there is a need for a technique of using gene expression data to identify the onset of AD for aiding in the diagnosis and treatment of AD.